Resources Management Microservice initial implementation

• Update of the structure of the inital codebase to match a microservice-based project (deletion of src in root, creation of resources-management module, .gitignore...)
• Creation of openapi.yaml specification for the resources-management microservice
• Initial implementation of the resources-management microservice (ready to be tested 😄)

To generate the openapi.yaml-generated code: mvn clean install

To run the microservice server: mvn spring-boot:run (running on port 8082)